1. It is highly unlikely that uninstalling and reinstalling OpenCPN is going to resolve anything, really. But if you can't resist the temptation, help yourself, it is equally unlikely that it makes the things worse.
2. You should have a look into the logfile to find out whether it contains some clues that could help isolate the problem. If the crash is related to displaying a chart, try to isolate on which one and create the simplest possible scenario we could reproduce. You should try to get fresh charts.
3. You should try disabling OpenGL if it is enabled or vice versa.
4. While OpenCPN is not running, move the complete data folder (C:\ProgramData\opencpn on Windows, ~/.opencpn on Linux ~/Library/Preferences/opencpn / on Mac ) to a backup location and see whether something was rotten in your local OpenCPN data. Do not delete it if you want to keep your waypoints, routes and tracks!
5. If on Linux, run opencpn from command line and see whether it produces a backtrace to help identify the cause of the crash.
6. Still on Linux, you can use gdb or another debugger to get the backtrace and help identify the cause of the crash.

Enable thw WMM World Magnetic Model please.

It makes no sense to use magnetic on true north facing mercator projections.

Ownship true north heading predictor is only displayed if true north value is available.

If HDT is not available in the nmea data stream we use HDM and variation from the WMM plugin to estimate an effective HDT.

• A disabled plugin, whether managed or un-managed, does not get loaded, and cannot be responsible for performance deterioration at run-time.
• There is some very small cost involved in inspection of all available plugins, enabled or not, during OCPN startup. This is a transient, probably 50 msec. or so.
• If you are having performance problems, look to the graphics system. Are you using OpenGL?